Delivering ocular implants into the eye

ABSTRACT

A method of deploying an ocular implant into Schlemm&#39;s canal of an eye. The method includes the steps of inserting a distal end of a cannula through a cornea of the eye and into an anterior chamber of the eye, the cannula having a distal opening extending from the distal end and through a side wall; placing the distal opening of the cannula into fluid communication with Schlemm&#39;s canal; advancing the ocular implant distally through the cannula with a delivery tool engaged with the ocular implant, a proximal portion of the ocular implant engaging the delivery tool proximal to a distal portion of the delivery tool; and disengaging the ocular implant and the delivery tool when the proximal portion of the ocular implant reaches the cannula distal opening. The invention also includes a system for practicing the method.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/146,587, filed Jan. 2, 2014, which is a divisional of U.S.application Ser. No. 13/330,592, filed Dec. 19, 2011, now U.S. Pat. No.8,663,150, the disclosures of which are incorporated herein byreference.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to the medical devices andtreatments for the eye. More particularly, the present invention relatesto systems, devices and methods for delivering ocular implants into theeye for treating glaucoma.

BACKGROUND OF THE INVENTION

According to a draft report by The National Eye Institute (NEI) at TheUnited States National Institutes of Health (NIH), glaucoma is now theleading cause of irreversible blindness worldwide and the second leadingcause of blindness, behind cataract, in the world. Thus, the NEI draftreport concludes, “it is critical that significant emphasis andresources continue to be devoted to determining the pathophysiology andmanagement of this disease.” Glaucoma researchers have found a strongcorrelation between high intraocular pressure and glaucoma. For thisreason, eye care professionals routinely screen patients for glaucoma bymeasuring intraocular pressure using a device known as a tonometer. Manymodern tonometers make this measurement by blowing a sudden puff of airagainst the outer surface of the eye.

The eye can be conceptualized as a ball filled with fluid. There are twotypes of fluid inside the eye. The cavity behind the lens is filled witha viscous fluid known as vitreous humor. The cavities in front of thelens are filled with a fluid known as aqueous humor. Whenever a personviews an object, he or she is viewing that object through both thevitreous humor and the aqueous humor.

Whenever a person views an object, he or she is also viewing that objectthrough the cornea and the lens of the eye. In order to be transparent,the cornea and the lens can include no blood vessels. Accordingly, noblood flows through the cornea and the lens to provide nutrition tothese tissues and to remove wastes from these tissues. Instead, thesefunctions are performed by the aqueous humor. A continuous flow ofaqueous humor through the eye provides nutrition to portions of the eye(e.g., the cornea and the lens) that have no blood vessels. This flow ofaqueous humor also removes waste from these tissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of theanterior chamber of the eye through the trabecular meshwork and intoSchlemm's canal as new aqueous humor is secreted by the epithelial cellsof the ciliary body. This excess aqueous humor enters the venous bloodstream from Schlemm's canal and is carried along with the venous bloodleaving the eye.

When the natural drainage mechanisms of the eye stop functioningproperly, the pressure inside the eye begins to rise. Researchers havetheorized prolonged exposure to high intraocular pressure causes damageto the optic nerve that transmits sensory information from the eye tothe brain. This damage to the optic nerve results in loss of peripheralvision. As glaucoma progresses, more and more of the visual field islost until the patient is completely blind.

In addition to drug treatments, a variety of surgical treatments forglaucoma have been performed. For example, shunts were implanted todirect aqueous humor from the anterior chamber to the extraocular vein(Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,”Investigative Ophthalmology (February 1966)). Other early glaucomatreatment implants led from the anterior chamber to a sub-conjunctivalbleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Stillothers were shunts leading from the anterior chamber to a point justinside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a newmethod to lower intraocular pressure in patients with POAG?” OphthalmicSurgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No.6,450,984).

SUMMARY OF THE DISCLOSURE

One aspect of the invention provides a method of deploying an ocularimplant into Schlemm's canal of an eye. In some embodiments, the methodincludes the steps of inserting a distal end of a cannula through acornea of the eye and into an anterior chamber of the eye, the cannulahaving a distal opening extending from the distal end and through a sidewall; placing the distal opening of the cannula into fluid communicationwith Schlemm's canal; advancing the ocular implant distally through thecannula with a delivery tool engaged with the ocular implant, a proximalportion of the ocular implant engaging the delivery tool proximal to adistal portion of the delivery tool; and disengaging the ocular implantand the delivery tool when the proximal portion of the ocular implantreaches the cannula distal opening.

In some embodiments, the disengaging step includes the step ofseparating the distal portion of the delivery tool and the ocularimplant from each other when the distal portion of the delivery toolpasses through the distal opening of the cannula. In some suchembodiments, the separating step is performed before the distal portionof the delivery tool reaches the distal end of the cannula. Theseparating step may include the step of maintaining contact between theocular implant and the cannula and moving the distal portion of thedelivery tool away from the cannula. In embodiments in which the distalportion of the delivery tool has an at-rest shape (such as, e.g., acurve having a smaller radius of curvature than a distal portion of thecannula), the separating step may also include the step of permittingthe distal portion of the delivery tool to assume its at-rest shape.

In some embodiments, the inserting step includes the step of placing thedistal end of the cannula in Schlemm's canal and a portion of thecannula distal opening outside of Schlemm's canal, the disengaging stepincluding the step of disengaging the ocular implant and the deliverytool while the proximal portion of the ocular implant is disposedoutside of Schlemm's canal. The disengaging step may also include thestep of disengaging the ocular implant and the delivery tool while theproximal portion of the ocular implant is disposed inside the anteriorchamber of the eye.

Some embodiments include the step of, after the disengaging step:re-engaging the delivery tool and the ocular implant; moving thedelivery tool and the ocular implant in a proximal direction to withdrawat least a portion of the ocular implant from Schlemm's canal; advancingthe ocular implant and delivery tool distally into Schlemm's canal; anddisengaging the ocular implant and the delivery tool.

The method's disengaging step may also include the step of disengagingan interlocking portion of the delivery tool from a complementaryinterlocking portion of the ocular implant.

Another aspect of the invention provides a system with a cannula havinga side wall defining a passageway, the cannula including an openingextending through a distal end and the side wall, the opening fluidlycommunicating with the passageway; an ocular implant disposed inside thepassageway defined by the cannula; a delivery tool having a distalinterlocking portion engaging a complementary interlocking portion ofthe ocular implant to form a mechanically interlocking connection whenthe interlocking portion of the delivery tool is proximal to the troughportion of the cannula.

In some embodiments, the distal interlocking portion of the deliverytool has an at-rest shape different from the shape of the cannula (suchas, e.g., a curve having a smaller radius of curvature than a radius ofcurvature of the cannula), the cannula side wall preventing the deliverytool from assuming its at-rest shape when the interlocking portion ofthe delivery tool is proximal to the trough portion of the cannula.

In some embodiments, the system also has a cannula subassembly includingthe cannula and a delivery tool subassembly including the delivery tool,the delivery tool subassembly and the cannula subassembly engaging oneanother at a keyed interface, the keyed interface being configured topermit the delivery tool to slide along the passageway defined by thecannula, and the keyed interface being configured to prohibit rotationof the delivery tool subassembly relative to the cannula subassembly sothat a predetermined orientation between the delivery tool and thecannula is maintained.

In some embodiments, the delivery tool subassembly includes a rotatingrack gear defining a shaped hole having a predetermined shape in lateralcross-section and the cannula subassembly including a shaped portionconfigured to cooperate with the shaped hole of the rotating rack gearso that the delivery tool is free to slide along the passageway definedby the cannula and rotation of the delivery tool relative to the cannulais prohibited.

In some embodiments, the opening extending through the distal end andthe side wall of the cannula is dimensioned and positioned such that,when the ocular implant reaches a predefined location along thepassageway, the delivery tool will move toward an undeformed shape inwhich the interlocking portion of the delivery tool disengages thecomplementary interlocking portion of the ocular implant to release theocular implant. The delivery tool may also have a cannula wallengagement surface diametrically opposite the interlocking portion and areduced diameter portion proximal to the interlocking portion.

In some embodiments, the mechanically interlocking connection isconfigured to preclude axial and/or movement of the ocular implantrelative to the delivery tool. The mechanically interlocking connectionmay include a peak of the delivery tool that is received in a valley ofthe ocular implant or a peak of the ocular implant that is received in avalley of the delivery tool.

In some embodiments, the system also includes a motion control mechanismconfigured to be operated from a location outside of the eye to move thedelivery tool and the ocular implant along the passageway defined by thecannula.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a stylized representation of a medical procedure in accordancewith this detailed description.

FIG. 2 is an enlarged perspective view further illustrating the deliverysystem and the eye shown in FIG. 1.

FIG. 3 is a stylized perspective view illustrating the anatomy of aneye.

FIG. 4 is a stylized perspective view showing Schlemm's canal and aniris of the eye shown in the previous figure.

FIG. 5 is an enlarged cross-sectional view further illustratingSchlemm's canal SC shown in the previous figure.

FIG. 6A is a perspective view showing a delivery system including anocular implant and a cannula defining a passageway that is dimensionedto slidingly receive the ocular implant.

FIG. 6B is an enlarged detail view further illustrating the ocularimplant and the cannula 108 shown in FIG. 6A.

FIG. 7 is a perspective view further illustrating delivery system 100shown in FIG. 6.

FIG. 8 is an exploded view illustrating various elements of a deliverysystem in accordance with the detailed description.

FIG. 8A is an end view of the rotating rack gear shown in FIG. 8.

FIG. 9 is an exploded perspective view further illustrating the deliverytool subassembly shown in the exploded perspective view of FIG. 8.

FIG. 10 is an exploded perspective view further illustrating the cannulasubassembly shown in the exploded perspective view of FIG. 8.

FIG. 11 is a cross-sectional view showing an assembly including both thedelivery tool subassembly and the cannula subassembly shown in theexploded perspective view of FIG. 8.

FIG. 12 is a perspective view of a cannula in accordance with thedetailed description.

FIG. 13 is a perspective view of an assembly including the cannula shownin FIG. 12 and an ocular implant that is resting in a passageway definedby the cannula.

FIG. 14 is a stylized perspective view including the assembly shown inFIG. 13.

FIG. 15 is an enlarged perspective view showing a portion of the cannulashown in the assembly of FIG. 14.

FIG. 16 is an additional perspective view showing the ocular implant andthe cannula shown in the previous Figure.

FIG. 17 is an additional perspective view showing the ocular implant andthe cannula shown in FIG. 16.

FIG. 18 is an additional perspective view showing the ocular implant andthe cannula shown in FIGS. 16 and 17.

FIG. 19 is a perspective view of Schlemm's canal after the cannula shownin FIG. 18 has been withdrawn leaving an inlet portion of the ocularimplant in the anterior chamber of the eye and the remainder of ocularimplant in Schlemm's canal.

FIGS. 20A-FIG. 20H are a series of stylized plan views illustratingexample methods in accordance with the detailed description andassociated apparatus used while performing those methods.

FIG. 21 is a perspective view showing a delivery tool subassembly 370that may be part of a delivery system (e.g., the delivery system shownin FIG. 8).

FIG. 22A is a stylized plan view further illustrating the delivery toolshown in FIG. 21. FIG. 22B is an additional stylized plan viewillustrating the cannula, ocular implant, and delivery tool shown inFIG. 22A.

FIG. 23 is a stylized plan view showing a delivery system including anocular implant disposed in a passageway defined by a cannula.

FIG. 24A is a stylized plan view further illustrating the cannula shownin FIG. 23. FIG. 24B is an additional stylized plan view illustratingthe cannula, ocular implant, and delivery tool shown in FIG. 24A.

FIG. 25A is a perspective view showing a delivery tool subassembly thatmay be part of a delivery system (e.g., the delivery system shown inFIG. 8). FIG. 25B is a perspective view of the distal end of thedelivery tool of this embodiment.

FIG. 26A is a stylized perspective view showing a cannula having adistal portion positioned so as to extend through the wall of Schlemm'scanal. An ocular implant is shown extending out a distal opening of thecannula and into Schlemm's canal. FIG. 26B is an additional perspectiveview showing the ocular implant and the cannula shown in FIG. 26A.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

FIG. 1 is a stylized representation of a medical procedure in accordancewith this detailed description. In the procedure of FIG. 1, a physicianis treating an eye 20 of a patient P. In the procedure of FIG. 1, thephysician is holding a hand piece of a delivery system 70 in his or herright hand RH. The physician's left hand (not shown) may be used to holdthe handle H of a gonio lens 23. Alternatively, some physicians mayprefer holding the delivery system hand piece in the left hand and thegonio lens handle H in the right hand RH.

During the procedure illustrated in FIG. 1, the physician may view theinterior of the anterior chamber using gonio lens 23 and a microscope25. Detail A of FIG. 1 is a stylized simulation of the image viewed bythe physician. A distal portion of a cannula 72 is visible in Detail A.A shadow-like line indicates the location of Schlemm's canal SC which islying under various tissues (e.g., the trabecular meshwork) thatsurround the anterior chamber. A distal opening 74 of cannula 72 ispositioned near Schlemm's canal SC of eye 20.

Methods in accordance with this detailed description may include thestep of advancing the distal end of cannula 72 through the cornea of eye20 so that a distal portion of cannula 72 is disposed in the anteriorchamber of the eye. Cannula 72 may then be used to access Schlemm'scanal of the eye, for example, by piercing the wall of Schlemm's canalwith the distal end of cannula 72. Distal opening 74 of cannula 72 maybe placed in fluid communication with a lumen defined by Schlemm'scanal. The ocular implant may be advanced out of distal opening 74 andinto Schlemm's canal. Insertion of the ocular implant into Schlemm'scanal may facilitate the flow of aqueous humor out of the anteriorchamber of the eye.

FIG. 2 is an enlarged perspective view further illustrating deliverysystem 50 and eye 20 shown in the previous figure. In FIG. 2, cannula 56of delivery system 50 is shown extending through a cornea 26 of eye 20.A distal portion of cannula 56 is disposed inside the anterior chamberdefined by cornea 26 of eye 20. In the embodiment of FIG. 2, cannula 56is configured so that a distal opening 58 of cannula 56 can be placed influid communication with Schlemm's canal.

In the embodiment of FIG. 2, an ocular implant is disposed in apassageway defined by cannula 56. Delivery system 50 includes amechanism that is capable of advancing and retracting the ocular implantalong the length of cannula 56. The ocular implant may be placed inSchlemm's canal of eye 20 by advancing the ocular implant through thedistal opening of cannula 56 while the distal opening is in fluidcommunication with Schlemm's canal.

FIG. 3 is a stylized perspective view illustrating a portion of eye 20discussed above. Eye 20 includes an iris 30 defining a pupil 32. In FIG.3, eye 20 is illustrated in a cross-sectional view created by a cuttingplane passing through the center of pupil 32. Eye 20 can beconceptualized as a fluid filled ball having two chambers. Sclera 34 ofeye 20 surrounds a posterior chamber PC filled with a viscous fluidknown as vitreous humor. Cornea 36 of eye 20 encloses an anteriorchamber AC that is filled with a fluid known as aqueous humor. Thecornea 36 meets the sclera 34 at a limbus 38 of eye 20. A lens 40 of eye20 is located between anterior chamber AC and posterior chamber PC. Lens40 is held in place by a number of ciliary zonules 42.

Whenever a person views an object, he or she is viewing that objectthrough the cornea, the aqueous humor, and the lens of the eye. In orderto be transparent, the cornea and the lens can include no blood vessels.Accordingly, no blood flows through the cornea and the lens to providenutrition to these tissues and to remove wastes from these tissues.Instead, these functions are performed by the aqueous humor. Acontinuous flow of aqueous humor through the eye provides nutrition toportions of the eye (e.g., the cornea and the lens) that have no bloodvessels. This flow of aqueous humor also removes waste from thesetissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of the eyeas new aqueous humor is secreted by the epithelial cells of the ciliarybody. This excess aqueous humor enters the blood stream and is carriedaway by venous blood leaving the eye.

Schlemm's canal SC is a tube-like structure that encircles iris 30. Twolaterally cut ends of Schlemm's canal SC are visible in thecross-sectional view of FIG. 3. In a healthy eye, aqueous humor flowsout of anterior chamber AC and into Schlemm's canal SC. Aqueous humorexits Schlemm's canal SC and flows into a number of collector channels.After leaving Schlemm's canal SC, aqueous humor is absorbed into thevenous blood stream and carried out of the eye.

FIG. 4 is a stylized perspective view showing Schlemm's canal SC andiris 30 of eye 20 shown in the previous figure. In FIG. 4, Schlemm'scanal SC is shown encircling iris 30. With reference to FIG. 4, it willbe appreciated that Schlemm's canal SC may overhang iris 30 slightly.Iris 30 defines a pupil 32. In the embodiment of FIG. 4, Schlemm's canalSC and iris 30 are shown in cross-section, with a cutting plane passingthrough the center of pupil 32.

The shape of Schlemm's canal SC is somewhat irregular, and can vary frompatient to patient. The shape of Schlemm's canal SC may beconceptualized as a cylindrical-tube that has been partially flattened.With reference to FIG. 4, it will be appreciated that Schlemm's canal SChas a first major side 50, a second major side 52, a first minor side54, and a second minor side 56.

Schlemm's canal SC forms a ring around iris 30 with pupil 32 disposed inthe center of that ring. With reference to FIG. 4, it will beappreciated that first major side 50 is on the outside of the ringformed by Schlemm's canal SC and second major side 52 is on the insideof the ring formed by Schlemm's canal SC. Accordingly, first major side50 may be referred to as an outer major side of Schlemm's canal SC andsecond major side 52 may be referred to as an inner major side ofSchlemm's canal SC. With reference to FIG. 4, it will be appreciatedthat first major side 50 is further from pupil 32 than second major side52. The outer major wall of Schlemm's canal is supported by scleraltissue of the eye. Elevated pressure inside the eye of a patientsuffering from glaucoma may cause the inside major wall of Schlemm'scanal to be pressed against the outer major wall of the canal.

FIG. 5 is an enlarged cross-sectional view further illustratingSchlemm's canal SC shown in the previous figure. With reference to FIG.5, Schlemm's canal SC comprises a wall W defining a lumen 58. The shapeof Schlemm's canal SC is somewhat irregular and can vary from patient topatient. The shape of Schlemm's canal SC may be conceptualized as acylindrical-tube that has been partially flattened. The cross-sectionalshape of lumen 58 may be compared to the shape of an ellipse. A majoraxis 60 and a minor axis 62 of lumen 58 are illustrated with dashedlines in FIG. 5.

The length of major axis 60 and minor axis 62 can vary from patient topatient. The length of minor axis 62 is between one and thirtymicrometers in most patients. The length of major axis 60 is between onehundred and fifty micrometers and three hundred and fifty micrometers inmost patients.

With reference to FIG. 5, Schlemm's canal SC comprises a first majorside 50, a second major side 52, a first minor side 54, and a secondminor side 56. In the embodiment of FIG. 5, first major side 50 islonger than both first minor side 54 and second minor side 56. Also inthe embodiment of FIG. 5, second major side 52 is longer than both firstminor side 54 and second minor side 56.

FIG. 6A is a perspective view showing a delivery system 100 including anocular implant 150 and a cannula 108 defining a passageway that isdimensioned to slidingly receive ocular implant 150. Delivery system 100may be used to advance ocular implant 150 into a target location in theeye of a patient. Examples of target locations that may be suitable insome applications include areas in and around Schlemm's canal, thetrabecular meshwork, the suprachoroidal space, and the anterior chamberof the eye. FIG. 6B is an enlarged detail view further illustratingocular implant 150 and cannula 108 of delivery system 100.

Delivery system 100 of FIG. 6A is capable of controlling the advancementand retraction of ocular implant 150 within cannula 108. Ocular implant150 may be placed in a target location (e.g., Schlemm's canal) byadvancing the ocular implant through a distal opening 132 of cannula 108while the distal opening is in fluid communication with Schlemm's canal.In the embodiment of FIG. 6A, ocular implant 150 has been advancedthrough distal opening 132 of cannula 108 for purposes of illustration.

Delivery system 100 of FIG. 6A includes a housing 102, a sleeve 104, andan end cap 110. A tracking wheel 106 extends through a wall of housing102 in FIG. 6A. Tracking wheel 106 is part of a mechanism that iscapable of advancing and retracting a delivery tool 152 of deliverysystem 100. The delivery tool 152 extends through a distal opening ofcannula 108 of FIG. 6B. Rotating the tracking wheel will cause deliverytool 152 to move in an axial direction along a passageway defined bycannula 108. The axial direction may be in a distal direction D or aproximal direction P.

In the embodiment of FIG. 6A, housing 102 is configured to be grippedwith one hand while providing control over the axial advancement andretraction of ocular implant via tracking wheel 106. The housing ofdelivery system 100 results in an advantageous ergonomic relationship ofthe fingers relative to the hand. This design provides a configurationthat will allow a user, such as a physician, to stabilize the deviceusing part of the hand, while leaving the middle or index finger freemove independently from the remainder of the hand. The middle or indexfinger is free to move independently to rotate the wheel for advancingand/or retract the ocular implant.

FIG. 6B is an enlarged detail view further illustrating ocular implant150 and a cannula 108 of delivery system 100. Cannula 108 comprises agenerally tubular member 198 having proximal portion 140, a distal end134, and a distal portion 144 extending between distal end 134 andproximal portion 140. In the embodiment of FIG. 6, distal portion 144 iscurved. In some useful embodiments, distal portion 144 is dimensionedand configured to be received in the anterior chamber of the eye.

FIG. 6B shows delivery tool 152 of delivery system 100 extending throughdistal opening 132 of cannula 108. Delivery tool 152 includes aninterlocking portion 160 that is configured to form a connection with acomplementary interlocking portion 162 of ocular implant 150, asexplained in more detail below. In the embodiment of FIG. 6, rotatingthe tracking wheel will cause delivery tool 152 and ocular implant 150to move along a path defined by cannula 108. Cannula 108 is sized andconfigured so that the distal end of cannula 108 can be advanced throughthe trabecular meshwork of the eye and into Schlemm's canal. Positioningcannula 108 in this way places distal opening 132 in fluid communicationwith Schlemm's canal. Ocular implant 150 may be placed in Schlemm'scanal by advancing the ocular implant through distal opening 132 ofcannula 108 while the distal opening is in fluid communication withSchlemm's canal. The distal portion of the cannula may include a cuttingportion configured to cut through the trabecular meshwork and the wallof Schlemm's canal, such as by providing distal end 134 with a sharpedge adapted to cut through such tissue.

FIG. 7 is a perspective view further illustrating delivery system 100shown in the previous figure. In FIG. 7, a portion of housing 102 hasbeen removed for purposes of illustration. Delivery system 100 includesa delivery tool subassembly 170 and a cannula subassembly 180. Deliverytool subassembly 170 includes rotating rack gear 120 and a delivery tool(not shown). In the embodiment of FIG. 7, the delivery tool extends intoa passageway defined by a cannula 108. Cannula 108 can be seen extendingbeyond sleeve 104 in FIG. 7. Cannula subassembly 180 includes cannula108, a hub 172, and an extension tube (not shown). In the embodiment ofFIG. 7, the extension tube of cannula subassembly 180 is disposed insidea lumen defined by rotating rack gear 120.

Delivery system 100 includes a mechanism 166 that controls the movementof delivery tool subassembly 170. Mechanism 166 includes a number ofcomponents that are located inside housing 102, including tracking wheel106, an idler gear 122, and the rotating rack gear 120. In theembodiment of FIG. 7, tracking wheel 106 and idler gear 122 are bothrotatably supported by housing 102. Gear teeth on tracking wheel 106engage gear teeth on idler gear 122, which in turn engage gear teeth onthe rotating rack gear 120. Rotating tracking wheel 106 in a counterclockwise direction CCW causes idler gear 122 to rotate in a clockwisedirection CW, which in turn causes the rotating rack gear 120 to move ina distal direction D. Rotating tracking wheel 106 in a clockwisedirection CW causes idler gear 122 to rotate in a counter clockwisedirection CCW, which in turn causes the rotating rack gear 120 to movein a proximal direction P. In other embodiments, the idler gear may beeliminated from the device, which would cause counter-clockwise movementof the tracking wheel to move the rack gear proximally.

In the embodiment of FIG. 7, a sleeve 104 is fixed to cannulasubassembly 180. Sleeve 104 may be rotated by the user to change theorientation of cannula 108 with respect to housing 102. The sleeve 104may include gripping features, such as grooves (as shown), a rubbercoating, or other frictional surfaces to facilitate this use. In someapplications, correct alignment between the cannula and iris isadvantageous to ensure that the core tube and/or ocular implant isadvanced at the correct trajectory relative to Schlemm's canal or otheranatomy in the eye into which the ocular implant is to be implanted. Thedevice is configured in a manner that keeps the ocular implant alignedwithin the device during rotation. Selected groups of components arekeyed together to ensure that they rotate as a single body whilesimultaneously allowing axial movement of the ocular implant. In theembodiment of FIG. 7, cannula subassembly 180 and delivery toolsubassembly 170 rotate in unison with sleeve 104 relative to housing102.

In the embodiment of FIG. 7, rotating rack gear 120 is configured torotate with sleeve 104 while maintaining the ability to move axially inthe distal and proximal directions before, during, and after rotation.As the rotating rack gear 120 moves distally and/or proximally, itcauses corresponding movement of the delivery tool relative to cannula108. This movement is transferred to ocular implant 150 when deliverytool 152 is coupled to ocular implant 150. Delivery tool subassembly 170and cannula subassembly 180 engage one another in a keyed arrangement,as described in more detail below. This keyed arrangement causesdelivery tool subassembly 170 and cannula subassembly 180 to maintain aconstant rotational orientation relative to each other while, at thesame time, allowing delivery tool subassembly 170 to translate in adistal direction D and a proximal direction P relative to cannulasubassembly 180.

FIG. 8 is an exploded view illustrating various elements of deliverysystem 100. Cannula subassembly 180 includes a hub 172 and an extensiontube 174 that are both fixed to cannula 108. Extension tube 174 includesa shaped portion 175 that is dimensioned and shaped to fit within ashaped through hole 177 (shown in FIGS. 8A and 11) within by rotatingrack gear 120. This keyed arrangement causes delivery tool subassembly170 and cannula subassembly 180 to maintain a constant rotationalorientation relative to each other while, at the same time, allowingdelivery tool subassembly 170 to translate in a distal direction D and aproximal direction P relative to cannula subassembly 180.

In some embodiments, delivery tool 152 is formed from shape memorymaterial (such as, e.g., nitinol), and at least a portion of deliverytool 152 assumes a curved at-rest shape when no external forces areacting on it. Delivery tool 152 can be urged to assume a straightenedshape, for example, by inserting delivery tool 152 through a straightportion of the passageway defined by cannula 108. When the delivery toolis confined, such as within cannula 108, the interlocking portion canengage the complementary interlocking portion to join the delivery tooland ocular implant together, and allow the delivery tool and ocularimplant to move together through the cannula 108, as described in moredetail below.

Delivery system 100 also includes an O-ring 126 disposed between sleeveand 104 and housing 102. O-ring 126 can provide friction and/orresistance between sleeve 104 and housing 102. This friction and/orresistance may be useful, for example, to hold the sleeve 104 in adesired orientation. A noseplug 105 snaps into the distal end of thedelivery system.

FIG. 9 is an exploded perspective view of delivery tool subassembly 170shown in the previous figure. Delivery tool subassembly 170 comprises adelivery tool 152, a rotating rack gear 120, and a spacer 176. Deliverytool 152 includes a shaped proximal portion 156, a curved distal portion153, a distal cannula engagement surface 161 and a reduced diameterportion 163 proximal to the distal cannula engagement surface 161.Spacer 176 is interposed between rotating rack gear 120 and shapedproximal portion 156 of delivery tool 152 to hold delivery tool 152 androtating rack gear 120 in a generally co-axial arrangement when deliverytool subassembly 170 is in an assembled state, as shown in FIG. 11.Distal cannula engagement surface 161 is adapted to slide along aninside surface of the cannula wall while the delivery tool 152 isengaged to ocular implant 150. Curved distal portion 153 of deliverytool 152 has an at rest curve that is greater (i.e., has a smallerradius of curvature) than the curved portion 144 of cannula 108.

FIG. 10 is an exploded perspective view of cannula subassembly 180.Cannula subassembly 180 comprises cannula 108, extension tube 174 andhub 172. In the embodiment of FIG. 10, cannula 108 defines a passageway138 that is dimensioned to slidingly receive an ocular implant and thedelivery tool shown in the previous figure. At the same time, extensiontube 174 of cannula subassembly 180 may be received inside a lumendefined by the rotating rack gear shown in the previous figure.

Extension tube 174 includes a shaped portion 175 that is dimensioned andshaped to fit within a shaped through hole defined by rotating rack gear120, as shown below in FIG. 11. This keyed arrangement causes deliverytool subassembly 170 and cannula subassembly 180 to maintain a constantrotational orientation relative to each other while, at the same time,allowing delivery tool subassembly 170 to translate in a distaldirection D and a proximal direction P relative to cannula subassembly180.

FIG. 11 is a cross-sectional view showing an assembly including deliverytool subassembly 170 and cannula subassembly 180 discussed above.Delivery tool subassembly 170 includes a delivery tool 152, a rotatingrack gear 120 and a spacer 176. In the cross-sectional view of FIG. 11,a shaped portion 156 of delivery tool 152 can be seen extending into aslot 123 extending from a central portion 181 a through hole 177 formedin rotating rack gear 120. (FIG. 8A shows an end view of rotating rackgear 120 and through hole 177.) In the embodiment of FIG. 11, aninterlocking portion 160 of delivery tool 152 is disposed in angularalignment with shaped portion 156. Spacer 176 is interposed betweenrotating rack gear 120 and delivery tool 152. In the exemplaryembodiment of FIG. 11, spacer 176 is shaped and dimensioned to holddelivery tool 152 and rotating rack gear in a generally co-axialarrangement. This arrangement creates an advantageous orientedrelationship of interlocking portion 160 with respect to the distalopening 132 of cannula 108 and ensures that interlocking portion 160 isunimpeded and readily disengages itself from the implant when it exitsand flexes through distal opening 132. In the exemplary embodiment ofFIG. 11, spacer 176 and rotating rack gear 120 are fixed to each otherat a weld joint 178. Weld joint 178 may be formed, for example, using alaser welding process.

Cannula subassembly 180 includes cannula 108, a hub 172, and anextension tube 174. Extension tube 174 is disposed about cannula 108.Extension tube 174 and cannula 108 may be fixed to one another, forexample, using a laser spot welding process. Hub 172 is fixed to anouter surface portion of extension tube 174 in the embodiment of FIG.11. In FIG. 11, extension tube 174 of cannula subassembly 180 can beseen extending into a shaped through-hole defined by rotating rack gear120 of delivery tool assembly 170.

In FIG. 11, delivery tool 152 can be seen extending into a passageway138 defined by a cannula 108 of cannula subassembly 180. Passageway 138defined by cannula 108 is sized to slidably enclose delivery tool 152and an ocular implant that is coupled to delivery tool 152. Deliverytool 152 is configured to form a connection with the ocular implant, sothat distal movement of the delivery tool can cause distal movement ofthe ocular implant within cannula 108. Delivery tool 152 may be used toadvance the ocular implant through a distal opening 132 of cannula 108in order to deliver the ocular implant into the eye. The assembly ofFIG. 11 may be rotated by the user to change the orientation of thecurved portion of cannula 108 with respect to the housing of thedelivery system. The keyed relationship between delivery toolsubassembly 170 and cannula subassembly 180 assures that the rotationalorientation between cannula 108 and the ocular implant/delivery toolstays constant while at the same time, allowing ocular implant/deliverytool to translate in a distal direction D and a proximal direction Prelative to cannula 108.

FIG. 12 is a perspective view of a cannula 108 in accordance with thepresent detailed description. Cannula 108 of FIG. 12 comprises agenerally tubular member 198 having a central axis 196. Generallytubular member 198 of FIG. 12 comprises a proximal portion 140, a distalend 134, and a distal portion 144 extending between distal end 134 andproximal portion 140. A distal opening surface 142 surrounds a distalopening 132 extending through the distal end and through a side wall ofcannula 108. A beveled edge 165 is disposed at the distal end of distalopening surface 142, extending from the distal end 134 to a proximalextent 167 of beveled edge 165. Tubular member 198 defines distalopening 132, a proximal opening 136, and a passageway 138 extendingbetween proximal opening 136 and distal opening 132.

In the embodiment of FIG. 12, proximal portion 140 of cannula 108 issubstantially straight, distal portion 144 of cannula 108 is curved, andcentral axis 196 defines a curvature plane 148. Curvature plane 148 maybe referred to as a plane of curvature. Curvature plane 148 dividescannula 108 into a first portion PA and a second portion PB. In theembodiment of FIG. 12, second portion PB is substantially a mirror imageof first portion PA. In FIG. 12, distal portion 144 is shown extendingbetween distal end 134 and proximal portion 140 with no interveningelements. In the embodiment of FIG. 12, distal portion 144 is curvedalong its entire length.

A method in accordance with this detailed description may include thestep of advancing the distal end 134 of cannula 108 through the corneaof a human eye so that distal end 134 is disposed in the anteriorchamber of the eye. Cannula 108 may then be used to access Schlemm'scanal of the eye, for example, by piercing the wall of Schlemm's canalwith the distal end 134 of cannula 108. The beveled edge 165 may beinserted into Schlemm's canal to place at least part of distal opening132 of cannula 108 in communication with Schlemm's canal, as discussedin more detail below. The ocular implant may be advanced out of a distalport of the cannula and into Schlemm's canal.

In the embodiment of FIG. 12, distal portion 144 of cannula 108 definesa trough 154. In some useful embodiments, trough 154 is configured toreceive the entire external cross section of an ocular implant as theocular implant is being advanced into Schlemm's canal. When this is thecase, trough 154 may have a depth dimension that is deeper than a widthof the ocular implant. This cannula configuration advantageouslyprevents the ocular implant from intersecting the layers of thetrabecular meshwork as the ocular implant is advanced into Schlemm'scanal. Trough 154 may also be configured to allow the proximal portionof the ocular implant to be released from the delivery tool, asdiscussed below.

FIG. 13 is a perspective view of an assembly including cannula 108 shownin the previous figure. For purposes of illustration, cannula 108 iscross-sectionally illustrated in FIG. 13. In FIG. 13, an ocular implant150 can be seen resting in a passageway 138 defined by cannula 108. Withreference to FIG. 13, it will be appreciated that distal portion 144 ofcannula 108 is curved so that central axis 196 of cannula 108 defines acurvature plane 148. With reference to FIG. 13, it will be appreciatedthat curvature plane 148 divides cannula 108 into a first portion and asecond portion PB. Only second portion PB of cannula 108 is shown in theillustrative embodiment of FIG. 13.

FIG. 14 is a stylized perspective view including the assembly shown inthe previous figure. In the embodiment of FIG. 14, a distal portion ofcannula 108 is shown extending through the wall of Schlemm's canal SC.The distal tip of cannula 108 may include a sharp portion configured forcutting and/or pierced the trabecular meshwork and the wall of Schlemm'scanal so that the passageway defined by the cannula can be placed influid communication with the lumen defined by Schlemm's canal. With thepassageway of the cannula placed in fluid communication with the lumenof Schlemm's canal, ocular implant 150 can be advanced out of the distalopening of the cannula and into Schlemm's canal. In FIG. 14, a distalportion of ocular implant 150 can be seen through distal opening 132 ofcannula 108.

For purposes of illustration, a hypothetical window W is cut through thewall of cannula 108 in FIG. 14. An interlocking portion 160 of adelivery tool 152 and a complementary interlocking portion 162 of ocularimplant 150 are visible through window W. In the embodiment of FIG. 14,interlocking portion 160 of delivery tool 152 and complementaryinterlocking portion 162 of ocular implant 150 are engaging each otherso that a proximal end 149 of ocular implant 150 is proximal to thedistal end 151 of delivery tool 152. Surface 161 of delivery tool 152rests against the wall of cannula 108 to prevent interlocking portion160 of delivery tool 152 and complementary interlocking portion 162 ofocular implant 150 from disengaging one another. When they are connectedin this fashion, delivery tool 152 and ocular implant 150 move togetheras the delivery tool is advanced and retracted relative to cannula 108by the delivery system mechanism.

FIG. 15 is an enlarged perspective view showing a portion of cannula 108shown in the previous figure. In some useful embodiments, cannula 108 iscurved to achieve substantially tangential entry into Schlemm's canalSC. In the embodiment of FIG. 15, cannula 108 is contacting an outermajor wall of Schlemm's canal SC at a point of tangency PT. Also in theembodiment of FIG. 15, a curved distal portion of cannula 108 isdimensioned to be disposed within the anterior chamber of the eye.

As shown in FIG. 15, the distal tip 134 and beveled edge of the cannula108 have been inserted into Schlemm's canal up to the proximal extent167 of beveled edge 165. In this position, ocular implant 150 can beseen extending into trough 154. In some useful embodiments, the ocularimplant has a radius of curvature that is larger than the radius ofcurvature of the cannula. This arrangement ensures that the ocularimplant will track along trough 154 as the ocular implant is urged in adistal direction by delivery system 100.

FIG. 16 is an additional perspective view showing ocular implant 150 andcannula 108 shown in the previous figure. By comparing FIG. 16 with theprevious figure, it will be appreciated that ocular implant 150 has beenadvanced in a distal direction D while cannula 108 has remainedstationary so that a distal portion of ocular implant 150 is disposedinside Schlemm's canal SC. Trough 154 opens into an elongate opening 132defined by edge 142 at the distal portion of cannula 108.

In the embodiment of FIG. 16, the elongate opening defined by thecannula provides direct visualization of the ocular implant as it isadvanced into Schlemm's canal. A configuration allowing directvisualization of the ocular implant has a number of clinical advantages.During a medical procedure, it is often difficult to monitor theprogress of the implant by viewing the implant through the trabecularmeshwork. For example, blood reflux may push blood into Schlemm's canalobstructing a physician's view the portion of the implant that hasentered Schlemm's canal. With reference to FIG. 16, ocular implant 150tracks along trough 154 as it is advanced distally along cannula 108.The trough opening allows the physician to monitor the progress of theimplant by viewing the implant structures as they advance through thetrough prior to entering Schlemm's canal. The trough opening also allowsthe physician to identify the position of the proximal end of the ocularimplant with respect to the incision made by the cannula to accessSchlemm's canal.

FIG. 17 is an additional stylized perspective view showing ocularimplant 150 and cannula 108. In the embodiment of FIG. 17, theinterlocking portions 160 and 162 of the delivery tool 152 and ocularimplant 150, respectively, can be seen entering the distal opening 132defined by cannula 108. As shown, ocular implant 150 has been advancedin a distal direction D (relative to the embodiment shown in theprevious figure) so that more of ocular implant 150 is disposed insideSchlemm's canal SC. Surface 161 opposite interlocking portion 160 ofdelivery tool 152 still rests against the inner wall of cannula 108 tokeep the delivery tool interlocked with ocular implant 150.

FIG. 18 is an additional stylized perspective view showing ocularimplant 150 and cannula 108. As shown in FIG. 18, the ocular implant 150and delivery tool 152 have advanced further distally so that deliverytool surface 161 and part of the reduced diameter portion 163 have nowpassed into opening 132, thereby permitting the delivery tool curvedportion 153 to move toward its curved at-rest shape so that the deliverytool engagement surface 160 disengages and moves away from itscomplementary engagement surface 162 on the ocular implant 150.

In some useful embodiments, the delivery tool may be colored to providevisual differentiation from the implant. After the disengaging from theocular implant, cannula 108 and delivery tool 152 can be withdrawn fromSchlemm's canal SC leaving the ocular implant 150 in the fully deployedposition shown in FIG. 18. After delivery of ocular implant 150 iscomplete, the delivery tool and the cannula may be removed from the eye,leaving at least a distal portion of the ocular implant in Schlemm'scanal.

FIG. 19 is a perspective view of Schlemm's canal SC after the cannula(seen in the previous figure) has been withdrawn leaving an inletportion of ocular implant 150 in the anterior chamber of the eye and theremainder of ocular implant 150 in Schlemm's canal. The presence ofocular implant 150 in Schlemm's canal may facilitate the flow of aqueoushumor out of the anterior chamber. This flow may include axial flowalong Schlemm's canal, flow from the anterior chamber into Schlemm'scanal, and flow leaving Schlemm's canal via outlets communicating withSchlemm's canal. When in place within the eye, ocular implant 150 willsupport the trabecular meshwork and Schlemm's canal tissue and willprovide for improved communication between the anterior chamber andSchlemm's canal (via the trabecular meshwork) and between pockets orcompartments along Schlemm's canal.

FIGS. 20A-FIG. 20H are a series of stylized plan views illustratingexample methods in accordance with this detailed description andassociated apparatus used while performing those methods. In FIG. 20A, adistal portion of cannula 108 is shown extending through the wall ofSchlemm's canal SC. In the embodiment of FIG. 20A, cannula 108 includesa sharp portion at its distal end 134 configured for cutting and/orpierced the trabecular meshwork and the wall of Schlemm's canal SC. Inthe embodiment of FIG. 20A, the distal end of cannula 108 has beenadvanced through the trabecular meshwork and the wall of Schlemm's canalSC and a passageway defined by cannula 108 has been placed in fluidcommunication with the lumen defined by Schlemm's canal SC.

FIG. 20B is an additional stylized plan view showing cannula 108 shownin the previous figure. In the embodiment of FIG. 20B, an ocular implant150 has been advanced out of a distal opening of cannula 108 and intoSchlemm's canal SC. In FIG. 20B, a distal portion of ocular implant 150is shown residing in a lumen defined by Schlemm's canal.

FIG. 20C is an additional stylized plan view showing ocular implant 150and cannula 108. In the embodiment of FIG. 20C, an interlocking portion160 of delivery tool 152 and complementary interlocking portion 162 ofocular implant 150 are both disposed near a trough portion of cannula108. Ocular implant 150 has been advanced in a distal direction D(relative to the embodiment shown in the previous figure) so that moreof ocular implant 150 is disposed inside Schlemm's canal SC. In FIG.20C, ocular implant is shown residing in a fully deployed position. Asshown in FIG. 20C, interlocking portion 160 of delivery tool 152 hasdisengaged from complementary interlocking portion 162 of ocular implant150.

In the embodiment of FIG. 20C, distal opening 132 defined by cannula 108is shaped and dimensioned so as to allow interlocking portion 160 ofdelivery tool 152 to extend therethrough when ocular implant 150 reachesthe fully deployed position shown in FIG. 20C. When surface 161 hasentered opening 132, a distal portion of delivery tool 152 is free toflex radially inward toward a curved, at-rest shape extending throughdistal opening 132 when ocular implant 150 reaches the fully deployedposition shown in FIG. 20C to disengage from the ocular implant.

FIG. 20D is a plan view of Schlemm's canal SC after cannula 108 has beenmoved away from ocular implant 150. After moving cannula 108 away fromocular implant 150, a physician may visually inspect the presentlocation of the ocular implant to determine whether that location isacceptable. If the physician determines that the present location isunacceptable, the physician may use the systems and methods describedherein to recapture and reposition the ocular implant. The figuresdescribed below illustrate exemplary methods and apparatus forrecapturing and repositioning the ocular implant.

In the embodiment of FIG. 20E, cannula 108 has been positioned so thatthe complementary interlocking portion 162 of ocular implant 150 isdisposed between cannula 108 and the interlocking portion 160 ofdelivery tool 152. Further distal movement of cannula 108 will causedelivery tool surface 161 to re-engage with the inner wall of cannula108, thereby moving the interlocking portion 160 of the delivery toolinto re-engagement with the ocular implant. The delivery tool and ocularimplant can thereafter be moved proximally, possibly together with thecannula, to reposition the implant for subsequent redeployment.

FIG. 20F is an additional stylized plan view showing ocular implant 150and cannula 108 shown in the previous figure. By comparing FIG. 20F withthe previous figure, it will be appreciated that delivery tool 152 andocular implant 150 have been moved in a proximal direction P so that aportion of ocular implant 150 has been withdrawn from Schlemm's canalSC. In the embodiment of FIG. 20F, the complementary interlockingportion of ocular implant 150 and the interlocking portion of deliverytool 152 have both been drawn into the passageway defined by cannula108. Also in the embodiment of FIG. 20F, the side wall of cannula 108 isholding the distal portion of delivery tool 152 in a deformed shape withthe interlocking portion of delivery tool 152 engaging the complementaryinterlocking portion of ocular implant 150.

FIG. 20G is an additional stylized plan view showing ocular implant 150and cannula 108 shown in the previous figure. In the embodiment of FIG.20G, ocular implant 150 has been advanced out of a distal opening ofcannula 108 and into Schlemm's canal SC. In FIG. 20G, a distal part ofocular implant 150 is shown residing in a lumen defined by Schlemm'scanal. In the embodiment of FIG. 20G, interlocking portion 160 ofdelivery tool 152 and complementary interlocking portion 162 of ocularimplant 150 are both once again located near a trough portion of cannula108. In FIG. 20G, ocular implant is shown residing in a second fullydeployed position. In the embodiment of FIG. 20G, the delivery tool 152has once again disengaged from ocular implant 150 by permittinginterlocking portion 160 of delivery tool 152 to move away fromcomplementary interlocking portion 162 of ocular implant 150

FIG. 20H is a stylized plan view showing ocular implant 150 andSchlemm's canal SC after the cannula (seen in the previous figure) hasbeen withdrawn leaving an inlet portion of ocular implant 150 in theanterior chamber of the eye and the remainder of ocular implant 150 inSchlemm's canal. When in place within the eye, ocular implant 150 willsupport the trabecular meshwork and Schlemm's canal tissue and willprovide for improved communication between the anterior chamber andSchlemm's canal (via the trabecular meshwork) and between pockets orcompartments along Schlemm's canal. Accordingly, the presence of ocularimplant 150 in Schlemm's canal will facilitate the flow of aqueous humorout of the anterior chamber.

With reference to the figures described above, it will be appreciatedthat methods in accordance with the present detailed description may beused to position at least a distal portion of an implant in Schlemm'scanal of an eye. In some cases, a proximal inlet portion of the ocularimplant may be left in the anterior chamber. An exemplary method inaccordance with the present detailed description may include the step ofadvancing a distal end of a cannula through a cornea of the eye so thata distal portion of the cannula is disposed in the anterior chamber ofthe eye. The cannula may be used to access Schlemm's canal, for example,by cutting and/or piercing the wall of Schlemm's canal with a distalportion of the cannula. A distal opening of the cannula may be placed influid communication with Schlemm's canal. The distal end of the ocularimplant may be advanced through the distal opening of the cannula andinto Schlemm's canal.

After delivering an ocular implant into Schlemm's canal, a physician mayvisually inspect the present location of the ocular implant to determinewhether that location is acceptable. If the physician determines thatthe present location is unacceptable, the physician may use the systemsand methods described herein to recapture and redeliver the ocularimplant. Recapturing and redelivering the ocular implant may include thesteps of forming a second connection between the delivery tool and theocular implant and moving the delivery tool and the ocular implant in aproximal direction so that at least a portion of the ocular implant iswithdrawn from Schlemm's canal. A distal part of the ocular implant maybe advanced into Schlemm's canal while the ocular implant is coupled tothe delivery tool at the second connection. The second connection may beselectively broken to release the ocular implant from the deliverysystem while the distal part of the ocular implant is disposed inSchlemm's canal.

FIG. 21 is a perspective view showing a delivery tool subassembly 370that may be part of a delivery system (e.g., delivery system 100 shownin FIG. 8). Delivery tool subassembly 370 of FIG. 21 comprises arotating rack gear 320 that is fixed to a delivery tool 352. Deliverytool 352 includes an interlocking portion 360 and a curved distalportion 353. Curved distal portion 353 of delivery tool 352 is biased toassume the curved at-rest shape shown in FIG. 21 when no external forcesare acting on it. Curved distal portion 353 of delivery tool 352 may beurged to assume a straightened shape, for example, when it is disposedin a straight portion of a passageway defined by a cannula. Optionalcut-outs 351 may be formed in the wall of delivery tool 352 to reducefriction during tool advancement by reducing the bending force. Thecannula wall may also hold interlocking portion 360 of delivery tool 352into engagement with a complementary interlocking portion of an ocularimplant to form a mechanically interlocking connection.

FIG. 22A is a stylized plan view showing delivery tool 352 shown in theprevious figure. In the embodiment of FIG. 22A, delivery tool 352 isextending into a passageway 338 defined by a cannula 308. A distalportion of cannula 308 defines a trough 354 that communicates with thepassageway 338 defined by the wall of cannula 308. Trough 354 opens outthe distal end of cannula 308. Trough 354 also opens into an elongateopening 332 defined by the edge 342 of the cannula wall.

In FIG. 22A, cannula 308 is illustrated in partial cross section.Interlocking portion 360 of delivery tool 352 and a complementaryinterlocking portion 362 of an ocular implant 350 are visible in FIG.22A. In the embodiment of FIG. 22A, interlocking portion 360 of deliverytool 352 and complementary interlocking portion 362 of ocular implant350 are engaging each other to form a mechanically interlockingconnection such that the implant's interlocking portion 362 is proximalto the delivery tool's interlocking portion 360. The delivery tool 352and ocular implant 350 may be selectively disengaged when interlockingportion 360 of delivery tool 352 is allowed to move away from anddisengage complementary interlocking portion 362 of ocular implant 350.In the embodiment of FIG. 22, the wall of cannula 308 is preventinginterlocking portion 360 of delivery tool 352 from moving away from anddisengaging complementary interlocking portion 362 of ocular implant350. A surface 363 of delivery tool 352 can be seen contacting the wallof cannula 308 at a point S in FIG. 22.

In FIG. 22A, interlocking portion 360 of delivery tool 352 is showndisposed within cannula passageway 338 at a location proximal of trough354 and distal opening 332. In some useful embodiments, opening 332 isdimensioned and positioned such that, when the ocular implant reaches apredefined location along the passageway, the distal portion of deliverytool 352 will be free to move toward a curved at-rest shape. When thedelivery tool assumes a curved shape, the interlocking portion of thedelivery tool moves away from and disengages the complementaryinterlocking portion of the ocular implant. In this way, delivery tool352 and ocular implant 350 may be selectively disengaged as deliverytool 352 is moved distally along the passageway defined by the cannulafrom a starting location proximal of opening 332.

FIG. 22B is an additional stylized plan view illustrating cannula 308,ocular implant 350, and delivery tool 352 shown in the previous figure.By comparing FIG. 22B with FIG. 22A, it will be appreciated thatdelivery tool 352 has been advanced in a distal direction D so thatdelivery tool 352 is extending through opening 332 and ocular implant350 is outside of cannula passageway 338. In the embodiment of FIG. 22B,interlocking portion 360 has moved away from complementary interlockingportion 362 and ocular implant 350 and delivery tool 352 havedisengaged.

FIG. 23 is a stylized plan view showing a delivery system 500 includingan ocular implant 550 disposed in a passageway 538 defined by a cannula508. FIG. 23 includes an enlarged detail view V illustrating a portionof cannula 508. For purposes of illustration, a hypothetical window W iscut through the wall of cannula 508 in FIG. 23. An interlocking portion560 of a delivery tool 552 and a complementary interlocking portion 562of ocular implant 550 are visible through window W. In the embodiment ofFIG. 23, interlocking portion 560 of delivery tool 552 and complementaryinterlocking portion 562 of ocular implant 550 are engaging each otherto form a mechanically interlocking connection. When delivery tool 552is confined, such as within cannula passageway 538, it can be held inmechanically interlocking engagement with ocular implant 550 so thatthese elements move together through passageway 538 of cannula 508. Anoptional ring 561 proximal to interlocking portion 560 and to theproximal end of implant 550 maintains the spacing between interlockingportion 560 and interlocking portion 562 so that they can be more easilydisengaged. The wall of cannula 508 prevents interlocking portion 560 ofdelivery tool 552 and complementary interlocking portion 562 of ocularimplant 550 from disengaging one another in the embodiment of FIG. 23. Asurface 565 of delivery tool 552 can be seen contacting the wall ofcannula 508 at a point S in FIG. 23.

Delivery system 500 of FIG. 23 may be used to advance ocular implant 550into a target location in the eye of a patient. Delivery system 500includes a housing 502 and a tracking wheel 506 that can be seenextending through the wall of housing 502 in FIG. 23. Tracking wheel 506is part of a mechanism that is capable of advancing and retractingdelivery tool 552 of delivery system 500. Rotating tracking wheel 506will cause delivery tool 552 to move in an axial direction along apassageway 538 defined by cannula 508. The axial direction may be in adistal direction D or a proximal direction P. Ocular implant 550 movesalong with delivery tool 552 as it is advanced and retracted relative tocannula 508 by the delivery system mechanism.

In the embodiment of FIG. 23, housing 502 is configured to be grippedwith one hand while providing control over the axial advancement andretraction of the ocular implant via tracking wheel 506. The design ofhousing 502 results in an advantageous ergonomic relationship of thefingers relative to the hand. This design provides a configuration thatwill allow a user, such as a physician, to stabilize the device usingpart of the hand, while leaving the middle or index finger free moveindependently from the remainder of the hand. The middle or index fingeris free to move independently to rotate tracking wheel 506 of deliverysystem 500 for advancing and/or retracting delivery tool 552.

FIG. 24A is a stylized plan view further illustrating cannula 508 shownin the previous figure. A distal portion of cannula 508 defines a trough554 that communicates with a passageway 538 defined by the wall ofcannula 508. Trough 554 opens out the distal end of cannula 508. Trough554 also opens into an elongate opening 532 defined by the edge 542 ofthe cannula wall. An ocular implant 550 and a portion of a delivery tool552 are disposed within cannula passageway 538. A distal portion ofdelivery tool 552 is biased to assume a curved at-rest shape when noexternal forces are acting on it. In the embodiment of FIG. 24A, thedistal portion of delivery tool 552 is disposed in a straight portion ofthe cannula passageway 538 so that it is urged to assume a straightenedshape.

FIG. 24B is an additional stylized plan view illustrating cannula 508,ocular implant 550, and delivery tool 552 shown in the previous figure.In FIG. 24B, delivery tool 552 is shown extending through opening 532and ocular implant 550 is shown in a location outside of cannulapassageway 538. In FIG. 24B, a gap can be seen between interlockingportion 560 of delivery tool 552 and a complementary interlockingportion 562 of ocular implant 550 in FIG. 24B. Accordingly, it will beappreciated that ocular implant 550 and delivery tool 552 havedisengaged. In the embodiment of FIG. 24B, the distal portion ofdelivery tool 552 has flexed through distal opening 532 as it hasassumed a curved shape.

Reference is now made to both FIG. 24A and FIG. 24B which may becollectively referred to as FIG. 24. In the embodiment of FIG. 24A, thedistal end of delivery tool 552 is disposed within cannula passageway538 at a location proximal of trough 554 and distal opening 532. In theembodiment of FIG. 24B, delivery tool 552 has been advanced in a distaldirection D so that delivery tool 552 is extending through opening 532.Opening 532 is dimensioned and positioned such that, when the ocularimplant reaches a predefined location along the passageway, the distalportion of delivery tool 552 will be free to move toward a curvedat-rest shape. When the delivery tool assumes a curved shape, theinterlocking portion of the delivery tool moves away from and disengagesthe complementary interlocking portion of the ocular implant. In thisway, delivery tool 552 and ocular implant 550 may be selectivelydisengaged as delivery tool 552 is moved distally along passageway 538from the position shown in FIG. 24A to the position shown in FIG. 24B.

FIG. 25A is a perspective view showing a delivery tool subassembly 770that may be part of a delivery system (e.g., delivery system 100 shownin FIG. 8). Delivery tool subassembly 770 of FIG. 25A comprises arotating rack gear 720 that is fixed to a delivery tool 752 formed as aflat ribbon. FIG. 25B is enlarged perspective view showing a distalportion of delivery tool 752. FIG. 25A and FIG. 25B may be collectivelyreferred to as FIG. 25. Delivery tool 752 of FIG. 25 includes aninterlocking portion 760 and a curved distal portion 753. Curved distalportion 753 of delivery tool 752 is biased to assume the curved at-restshape shown in FIG. 25 when no external forces are acting on it. Curveddistal portion 753 of delivery tool 752 may be urged to assume astraightened shape, for example, when it is disposed in a straightportion of a passageway defined by a cannula. The cannula wall may alsohold interlocking portion 760 of delivery tool 752 into engagement witha complementary interlocking portion of an ocular implant to form amechanically interlocking connection.

FIG. 26A is a stylized perspective view showing a cannula 708 having adistal portion positioned so as to extend through the wall of Schlemm'scanal SC. The distal tip of cannula 708 may include a sharp portionconfigured for cutting and/or pierced the trabecular meshwork and thewall of Schlemm's canal so that a passageway 738 defined by the cannulacan be placed in fluid communication with the lumen defined by Schlemm'scanal. With the passageway of the cannula placed in fluid communicationwith the lumen of Schlemm's canal, an ocular implant 750 can be advancedout of the distal opening of the cannula and into Schlemm's canal.Insertion of the ocular implant into Schlemm's canal may facilitate theflow of aqueous humor out of the anterior chamber of the eye.

In FIG. 26A, delivery tool 752 is shown extending out of passageway 738defined by a cannula 708. A surface 767 of delivery tool 752 restsagainst an inner wall surface of cannula 708 to keep delivery tool 752interlocked with ocular implant 750. A distal portion of cannula 708defines a trough 754 that communicates with passageway 738 defined bythe cannula wall. Trough 754 opens out the distal end of cannula 708.Trough 754 also opens into an elongate opening 732 defined by the edge742 of the cannula wall.

FIG. 26B is an additional perspective view showing ocular implant 750and cannula 708 shown in the previous figure. By comparing FIG. 26B withthe previous figure, it will be appreciated that ocular implant 750 anddelivery tool 752 have advanced further distally so that part ofdelivery tool surface 767 and part of distal curved portion 753 have nowpassed through opening 732, thereby permitting the distal tool portionto move toward its curved at-rest shape so that the delivery toolinterlocking portion 760 disengages and moves away from itscomplementary interlocking portion 762 on the ocular implant 750.

Reference is now made to both FIG. 26A and FIG. 26B which may becollectively referred to as FIG. 26. In the embodiment of FIG. 26,ocular implant 750 tracks along trough 754 as it is advanced distallyalong cannula 708. The trough opening allows the physician to monitorthe progress of the implant by viewing the implant structures as theyadvance through the trough prior to entering Schlemm's canal. The troughopening also allows the physician to identify the position of theproximal end of the ocular implant with respect to the incision made bythe cannula to access Schlemm's canal. Additionally, the trough openingallows the physician to see when the delivery tool is going to releasethe implant to monitor when he or she will lose the ability to retractthe implant.

While exemplary embodiments of the present invention have been shown anddescribed, modifications may be made, and it is therefore intended inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

What is claimed is:
 1. A method of deploying an ocular implant intoSchlemm's canal of an eye, the method comprising: inserting a distal endof a cannula through a cornea of the eye and into an anterior chamber ofthe eye, the cannula comprising a side wall defining a passageway, anopening in fluid communication with the passageway and extending throughthe side wall and a distal end of the cannula to define a trough havinga depth dimension deeper than a width of the ocular implant, and adistal opening surface surrounding the opening; inserting a distal endof the trough through trabecular meshwork into Schlemm's canal to placethe distal opening of the cannula in fluid communication with Schlemm'scanal; and advancing the ocular implant distally through the cannulainto Schlemm's canal without the ocular implant intersecting thetrabecular meshwork.
 2. The method of claim 1 wherein the cannulacomprises a bevel at a distal end of the trough, the method furthercomprising inserting the bevel into Schlemm's canal.
 3. The method ofclaim 1 wherein the inserting step comprises inserting only a part ofthe trough into Schlemm's canal.
 4. The method of claim 1 wherein theinserting step comprises inserting only part of the opening intoSchlemm's canal.
 5. The method of claim 1 wherein the advancing stepcomprises placing a distal end of the ocular implant in Schlemm's canalwhile a proximal end of the ocular implant is within the cannulaproximal to the trough.
 6. The method of claim 1 wherein the ocularimplant and delivery tool are interlocked during the advancing step, themethod further comprising disengaging interlocking portions of theocular implant and the delivery tool when a portion of the ocularimplant is in Schlemm's canal.
 7. The method of claim 6 wherein thedisengaging step comprises disengaging the delivery tool from the ocularimplant when the interlocking portions are in the trough.
 8. The methodof claim 7 wherein the disengaging step comprises moving the deliverytool away from the ocular implant.
 9. The method of claim 8 wherein themoving step comprises permitting the delivery tool to move toward acurved at-rest position.
 10. The method of claim 6 further comprisingreengaging the ocular implant and the delivery tool after thedisengaging step.
 11. The method of claim 10 further comprising movingthe ocular implant proximally after the reengaging step.
 12. The methodof claim 1 wherein the delivery tool is engaged with the ocular implantduring the advancing step, the method further comprising disengaging thedelivery tool from the implant when a distal portion of the implant isin Schlemm's canal and a proximal portion of the implant is in theanterior chamber.
 13. A system comprising: a cannula comprising a sidewall defining a passageway, an opening in fluid communication with thepassageway and extending through the side wall and a distal end of thecannula to define a trough having a depth dimension, and a distalopening surface surrounding the opening; an ocular implant disposedinside the passageway defined by the cannula, the ocular implant havinga width less than the depth dimension of the trough; and a delivery toolengaged with the ocular implant within the passageway and adapted tomove the implant distally into the trough and through the opening intoSchlemm's canal of a patient's eye when the cannula opening is in fluidcommunication with Schlemm's canal.
 14. The system of claim 13 whereinthe cannula further comprises a beveled edge at a distal end of thecannula.
 15. The system of claim 13 wherein the cannula comprises acurved distal portion, the trough being disposed in the curved distalportion.
 16. The system of claim 15 wherein the ocular implant has aradius of curvature greater than a radius of curvature of the curveddistal portion of the cannula.
 17. The system of claim 15 wherein thedelivery tool has a distal interlocking portion engaging a complementaryinterlocking portion of the ocular implant to form a mechanicallyinterlocking connection when the interlocking portion of the deliverytool is proximal to the trough in the passageway, the delivery tooldistal interlocking portion having a curved at-rest shape having asmaller radius of curvature than a radius of curvature of the cannuladistal portion, the cannula side wall preventing the delivery tooldistal interlocking portion from assuming its at-rest shape when thedelivery tool distal interlocking portion is proximal to the troughportion of the cannula.
 18. The system of claim 13 further comprising amechanism adapted and configured to maintain orientation of the deliverytool and the implant within the passageway of the cannula.
 19. Thesystem of claim 18 wherein the mechanism comprises a keyed interfacebetween the cannula and the delivery tool.
 20. The system of claim 13wherein the delivery tool has a distal interlocking portion engaging acomplementary interlocking portion of the ocular implant to form amechanically interlocking connection when the interlocking portion ofthe delivery tool is proximal to the trough in the passageway.